The long-term goal of our research program is to understand the mechanism(s) of gene activation in a eukaryotic system. The organism of choice for our work is Drosophila owing to the facility with which biochemical, cytological, and genetic techniques can be applied. This proposal concerns specifically the use of monoclonal antibodies to identify the nonhistone chromosomal proteins involved in gene activation. The antibodies obtained will be used to assess the amount and distribution of the protein and to carry out certain experiments to help delineate the role of the protein in gene activation and transcription. Further, the antibodies will be used either directly in, or as an assay for, protein purification, in work aimed at cloning the genes for these NHC proteins. Such recombinant DNA clones will permit studies on the structure, organization, expression, etc. of the genes. Our ultimate goal is to obtain conditional mutants of these proteins to permit a definitive analysis of their role in vivo and in vitro. Understanding of the process of gene activation should help us achieve greater understanding of differentiation and development, aiding in our analysis of related human health problems of cancer and aging.